One day, we’ll reach the maximum extraction of petroleum, or what’s called “peak oil,” according to a theory that’s been around since the 1950s. But peak oil is currently nowhere in sight, as more petroleum reserves are discovered, and drilling becomes more sophisticated. Another theory could end up overriding the idea that we’ll keep using oil until nothing’s left: peak demand is the point at which the world’s thirst for oil starts to decrease, and some energy companies are incorporating this idea into their business strategy.

“If you listen to the IEA…they believe we’re not going to hit peak demand until past 2040,” Smith says. “If you listen to one of the oil majors, such as Royal Dutch Shell, they believe it could happen as early as mid-next decade.”